Method of manufacturing staple fiber

ABSTRACT

Staple fibre from viscose is obtained by a continuous operation wherein filaments from a large number of spinning nozzles are combined to form a thick bundle and led vertically upwards and downwards a number of times over a series of rolls or similar deviating members, the thick bundle while travelling upwards being freed from tension, washed and, if desired, desulphurized, bleached, and again washed, the treatment liquid flowing in counter current, and the bundle is then passed to drying devices such as heated rollers, and to cutting devices.  The filament bundle may be treated with dilute ammonia or soda solution during the first washing process so as to neutralize acids.  In order to free the bundle from tension during the liquid treatment, the rollers may be rotated at different speeds or brake rods or plates may be provided.  The filament bundle may be cut to staple fibre while still containing a considerable amount of moisture.  The bundle may be curled by passing it while damp between grooved drying plates or rods arranged in the form of a grid.  The plates may be heated electrically, by gas flames, or by heated air.  They may be on endless bands and moved in the direction of the filaments.  As shown in Fig. 2, a large number of filaments 5 are combined together by rollers 17 and guides 18 to form a thick bundle 21 which passes up and down between rollers 22-37.  The upper rollers are driven at a lower peripheral speed than the lower rollers so that the filaments are free from tension during the upward run, and under tension when moving downwards.  Washing liquid is applied to the upwardly moving filaments from spraying nozzles 24, 38, 39, 40.  Dilute soda solution is applied from the nozzles 41, and water from nozzle 42.  The filament bundle passes to a drying drum 44 and then &lt;PICT:0443076/IV/1&gt; &lt;PICT:0443076/IV/2&gt; &lt;PICT:0443076/IV/3&gt; cutting device 51.  As shown in Fig. 3, the curling device consists of drying plates 53, 54 with interengaged grooves.  As shown in Fig. between grooved drying plates 49, 50 travelling on endless bands in the direction of the bundle.  The curled filament bundle then reaches a 4, closely arranged rods in grid form between which the bundle passes in a sinuous path are used as the curling device.

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' Patented Dec.l 29, 1936 UNITED STATES METHOD o'F MANUFACTURING s'rAPLE man Erhard Witte,

Berlin-Lichterfelde. Germany,

assignor to North American Rayon Corporation, New York, N. Y., a corporation of Dela- Ware Germany July 3, 1934 Application .June 27, 1935, serial No. 28,619

9 Claims.

The present invention relates the manufacture of articial silk filaments from a. cellulosic spinningsolutiom but primarily-has for its object the production of staple ber in a continuous operation.

It has heretofore been the practice to produce staple fiber from artificial silk by first twisting a large numberof freshly spun threads into a rope-like hank and then Winding it upon reels in order to be subjected to the usual after-treatment. Since these rope-like hanks possess a tensile'strength of 10,000 denier or more, it is obvious that the hanks require strong and costly machinery.

In accordance with another well-'known method, the cutting of the single threads is carried out immediately upon spinning of the same, and the short pieces of thread are then subjected to the usual after-treatment. It has also been proposed to intermittentlystop the extrusion of the spinning solution through the s'pinnerettes in order to produce short pieces of thread. The aftertreatment of these short pieces of thread, however, require many manipulations which increase Another object of the present invention is the employment of an intermediate treatment of the undivided thread with a diluted soda solution.

Still another object is the control of the drying process which is carried out in two stages.

These and other objects ofthe present invention will become more apparent from a study of the following description and by reference to the attached drawings, wherein:

Fig. I is a top or plan view of the entire machine; v

Fig. l1 is a vertical longitudinal view of Fig. I;

Figs. III and IV are enlarged detail verticalsectional views disclosing modifiediconstructions of drying plates or drying rollers through, which the thread bundle may be passed.

Referring now more particularly to the drawings in which' like numerals indicate like parts, the new device comprises two troughs I and 2 arranged at rectangular position with respect to each other. These troughs are divided into a number of spinning grooves 4 through the partitions 3. Each of these spinning grooves contains a. spinning pipe provided with a spinnerette through which artificial laments having 1000 denier each are extruded into the spinning bath. The spinning pipes, spinnerettes and artificial threads within the troughs are not shown in the drawings. After leaving the spinning bath the threads 5'are grouped together by means of thread guides 6, 1 and 8`from the trough I, and 9, I0 and II from the trough 2, and then united into thread bundles I4 and I5 through the thread guides I2 and I3, respectively. These thread bundles I4 and I5 are passed over freely rotating rollers I6 and I1 and then led to the actual takeup roller I9 by means of the thread guide I8. The take-up roller I9 is positively driven by the shaft 20 and gear wheels 53; the circumferential y the take-up roller I9 is led to the roller 22 rotating at the same circumferential speed as the roller I9 and driven by gear 54, and is then passed to the positively driven roller 23 which rotates at a peripheral speed of only 58 meters per minute and is driven by gear 55. Between the rollers 22 and 23 the thread bundle 2| rises vertically and is washed with warm water of approximately 3040 C. supplied by the spray nozzle 24; the flow of the water being countercurrent to the directionof travel of the thread bundle. The major portion of the precipitating bath adhering to the thread bundle willthus be removed and is collected in the receiver 25 in order to be used again if desired. From the roller 23 the thread bundle is led to the roller 28 by way of freely rotating guide rollers 25 and 21. rotates at the same peripheral speed as the roller 22 and is driven by gear 56, thus eiecting a tension `of the thread bundle between the rollers 23 and 29. This up and down passage of the thread- T bundle 2l is repeated a plurality of times. The

upward movement is carried out' without tension while during the downward movement a ten- 15' sion is imparted to the thread bundle. During this passage the peripheral speed of the rollers 30, 32, 34 and 36 driven by gears 51, 59, 59 and 60, respectively, is approximately 60 meters per minute while that of the rollers 29, 3l, 33, 35 and 3l driven by gears 6I, 62, 53, 64 and 65, respectively,

is approximately 58 meters per minute. During.

the upward movement of the thread bundle, i. e., when no tension is imparted thereto, the thread bundle is subjected to a wet-treatment by means of the spray nozzles 38,' 39, 40, 4I and 42.

The -roller 28' The spray nozzles 38, 39 and 40 are provided oo'y \ mately 0.5% solution), in order to remove any residues of acid which might still be contained in the thread bundle. In order to remove the soda solution from the thread bundle, an additional treatment withwater through the spray nozzle 42 is provided. From the roller 31 Athe thread bundle is passed over freely movable guiding devices 4.3 to a drying cylinder 44, whereby the rollers 45, 46, 41 and 48 press the thread bundle onto the drying cylinder 44 in order to `facilitate its guidance. The drying vcylinder 44 which rotates at atcircumferential speed of approximately 60 meters per minute reduces the moisture content of the thread bundle to about from 30 to 50%. After passing the. drying cylinder 44 the -thread bundle Vis led through grooved drying plates 49 and 50 which by means of belt-conveyors rotate in the direction of travel of the thread bundle. During the passage through the grooved drying plates the thread bundle obtains a corresponding curling and is at the same time completely dried. The thread bundle is then led to the cutting device L By means of wellknown rotating cutters the thread bundle is cut into the desired staple length and then drops into the receiver 52.

Two modifications of the drying plates 49 and ill are shown in Figures IH and IV. In accordance with Fig. III the drying plates are so constructed that the grooves of the upper plate Bl engage with the elevations of the lower plate S5, and vice versa. In accordance with Fig. IV rods 68 arranged closely together are provided instead of grooved drying plates. It is advisable to construct these rods freely rotatable; they form a kind of a grate through which the thread bundle passes in a. wavy motion. The heating of the grooved drying plates may either be effected by .electric heating elements, or the drying plates together with the endless belt-conveyors by vmeans of which they are moved may be arranged within a box which is heated through hot air supplied thereto.

In accordance with a special method of carrying out the process it is also provided that the drying between the drying plates and the like does not produce a product having the commercially customary moisture content, but a moisture content of approximately 20 to 25%,' because it is thus much easier to cut the thread bundle in the cutting device into the desired staple length.

What is claimed is:

1. In the continuous production of staple liber from threads o1 artificial origin the steps comprislng wet-treating a freshly extruded bundle of threads by passing the said bundle vertically upwardly and downwardly over a plurality of rollersLwet-treating said bundle in fits upward passage only under little or no tension, drying the threads, and then passing them to a cutting device.

2. In the continuous production of staple flber .from threads of artificial origin the steps comprising wet-treating a freshly extruded bundle of threads by passing the lsaid bundle vertically upwardly and downwardly over a plurality of y rollers,`wettreating said bundle in its upward passage only under little or no tension, drying the threads, curling thesaid threads during. the Saiddrying step, and then passing them to a cutting device.

3. In the continuous production of staple iiber from threads of artificial origin the steps comprising wet-treating a freshly extruded bundle of threads by passing the said bundle vertically upwardly and downwardly over a plurality of rollers, drying the threads, curling them, and4 then passing them to a cutting device.

5. In the continuous production of staple liber from threads of artificial origin the steps comprislng wet-treating a freshly extruded bundle of threads by passing the said bundle vertically upwardly and downwardly over a plurality of rollers, wet-treating said bundle in its upward passage over said rollers, drying saidbundle rst to a moisture content of from 30 to 50%, then, subsequently, drying it to a moisture content of from 20 to 25% by passing said bundle through grooved plates being rotated in the direction of travel of the thread bundle by means Vof an endless belt-conveyor, land prior to cutting.

6. In the continuous production of staple fiber from threads of artificial origin the steps comprising wet-treating `a freshly extruded bundle of threads by passing the said bundle 'vertically upwardly and downwardly over a plurality of rollers, wet-treating said bundle under only the tension produced by the weight of the said bundle while being passed'vertically upwardly over said rollers, drying said bundle to a moisture content of from30 to 50%, further drying said bundle, and then passing said bundle to a cutting device.

7. In the continuous production of staple lber from threads of articial origin the steps com prislng wet-treating a freshly extruded bundle of threads by passing the4 said bundle vertically upwardly and downwardly over a plurality of rollers, wet-treating said bundle in its upward passage/over said rollers under only the tension produced by the'weight'of said bundle, drying said bundle rst to a moisture content of from 30 to 50%, then, subsequently, drying it to a moisture content of from 20 to 25% by passing said bundle through grooved plates being rotated in the direction of travel of the thread bundle by means of an endless belt-conveyor, and prior to cutting.

8. In the continuous production of threads of f articial origin the steps comprising wet-treating a freshly extruded bundle of threads by passing the said bundle upwardly and downwardly over a plurality of rollers, wet-treating said ERHARD Wn'ra. 

